Recent changes to the Commonwealth Electoral Act have the effect of making it more difficult for micro parties to get elected in the Senate.
In Queensland, as this article by Amy Remeikis shows, manouevering by the Queensland Labor Government used an Opposition sponsored Bill to change the State electoral law to require compulsory preferential voting instead of optional preferential voting.
Optional preferential voting favoured the Labor Party when introduced. It meant that conservative votes in seats with Liberal and National party candidates could end up split. However, this advantage was lost when the conservative parties merged.
The system of optional preferential voting then became a threat to Labor where it is in competition with other non-conservative parties (such as the Greens).
As Remeikis explains, the Labor Party found an opportunity to return to compulsory preferential voting by adding this change to an opposition Bill to increase the number of electorates.